Alloy for coating with metal.



cnannnsr. nuaenss, or mamson, WISCONSIN, Assrenoa ro unrrnn sra'rns snnaaanrzme company, or NEW CASTLE, rnunsrnvanm, acoaroaarron or NEW JERSEY.

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Specification of Letters Patent.

ALLOY FOB COATTITG METAL no Drawing. Original application as June 16, ielaa'enal no. 58:7,244. Dividedand' this application filed December 2, 1910. Serial no. 595,205. l

To all whom it may concern:

a citizen of the United States, residing at Madison, county of Dane, and State of Wis consin, have invented certain new and useful, Improvements in Alloys for Coating with Metal, (division of my application, Se-

rial No. 567,244,. filed June 16, 1910,). of

which the following is a specification.

My present invention comprises an alloy or composition of matter in granular formand consisting largely of zinc. It also comprises a method whereby this alloy or composition may be produced in condition for use in coating iron to protect it from corrosion.

According. to the well-known method of. hot galvanizing, the iron or steel articles to be coated are dipped in fused zinc, which is held in an iron receptacle with a layer of sal-ammoniac floating on its surface to serve as a flux; It is well known that the molten zinc dissolves ofi some of the iron of the article under treatment, and also eats away the iron tank or receptacle by combining therewith. It is also known that the combined zinc .and iron settle to the bottom of the tank, and must be taken outkfrom time to time, otherwise the bath becomes dirty and will not stay sufliciently liquid at the working temperature of the flux. The mate rial thus removed from the hot galvanizing bath analyzes about 3% to 7% iron, and 97% to 93% zinc, with lead and other impurities, and issold onthe market at a relatively low price as ross. The material is somewhat harder th 11 zinc, and relatively tough and strong. r

According to the preferred embodiment of the present invention, galvanizers dross is utilized as thebasis for the production, in

novel manner, of an alloy or composition of matter containing zinc and iron, and having extreme brittleness, and having also other special characteristics which render it valuable for use in the arts.

To make up'the alloy or composition, zinc dross of ordinary commercial purity is crushed or broken into lumps and is then placed in a rotar iron drum, together with a quantity of re atively pure iron, suchaswrought iron, or electrolytic iron, in the form of chunks or small pieces. This charge of dross and iron is then heated to red heat Be. it known that I, CHARLES F. Bonuses,

I stices .the melting point of the dross, the iron and dross appear to combine, and the iron, as

such. disappears. By adding the iron in sultable proportions, all of the iron may be caused to combine with the dross, yielding an alloy of about the composition FeZn This alloy has properties dlfiering in many ways from those of its constituent metals. It is exceedingly brittle, and the rotation of the drum causes the lumps or particlesof alloy to grind on, one another, thereby re ducing substantially the entirecharge to a granular condition. 'The alloy, when thus reduced to granular condition, can be heated to a temperature in the neighborhood of 1300 degrees -Fahr.i without fusion .and without sinteringfof the particles into a coherent mass. In this respect, it is quite difl'erent from pulverized zinc, which fuses at about .740 degrees Fahr. When in granular condition, the alloy FeZn is light gray, and theindividual granules or particles appear to be regularly crystalline in structure.

The alloy, when in granular state, is in condition for use according to a method described and claimed in my co-pending application Serial No. 552,940, filed April 2, 1910, said method including heat treatment of an iron article while in contact with a brittle zinc alloy, with the result that the iron ar-- ticle takes on a protective coating. However, I have found that under some circumstances it is best that the granular material should contain more zinc than is represented by the symbol FeZn I have found. that this excess'of zinc may be put inas follows: After enough iron has been .added to the zinc dross to form a hi hly brittle alloy, and after this alloy has een tumbled. in the drum at red "heat until it has ground itself to the desired fineness, I add lumps or chunks of zinc, or of galvan'izers dross to the charge in the drum, and again tumble the contents. I have found that the lumps of zinc or dross disappear as if b vaporization, apparently difi'using throug the intero the entire granular mass and collecting on the grains or crystals of FeZn thereby raising the zinccontent of the mass without destroyingits brittleness and without changing it from its granular condition.

Patented aan. 16, rate.

The material so produced doesinot oxidize readily andiwill not explode; The exact amount of zinc added to enrichthe original brittle alloy may'vary through wide limits,

' but an addition of 5% is suitable.

. When using this granular material to produce a protective or ornamental coating on iron or steel articles, as described and claimed in .my parent application, Serial No. 567,244, the articles are first suitably cleaned by sand-blasting and pickling, or the like, and are then put in the rotary drum with the granular material and there heated until they take on a protective coating or covering. The temperature and duration of heatin can be suitably'regulated to govern the thickness of the coating. Heating for two hours and to a maximum temperature of about 850 degrees Fahr. gives good results when the granular material contains about 5% zinc over and above that chemically combined as FeZn By repeated use of the granular material, some of its zinc content may be used up by combining with iron from the articles to becoated or in other ways, making desirable the replenishment of the granular mass with zinc. This may be done without interrupting the normal operation merely by adding piecesof scrap zinc or lumps-of zmc dross when the charge of iron articles is being added to the drum. During the subsequent rotation of the drum, the high temperature and the grinding action of the charge effectively vaporize or break u the zinc lumps or scraps and distribute t e material uniformly throughout the granular mass 'tals or granules, bringin mg agents to smooth the surface of the iron and of the coating while the coating is being produced. The granular mass is not readily inflammable and can be exposed tothe air even at red heat Without exploding.

The coating produced on the ironarticles, as herein described, is very dense, and silver white in color, and has a chemical composition of about FeZn throughout the reater art of its thickness. It is hard an dense 1n structure and has an electrical potential with respect to electrolytes, slightly above that of pure iron. Being electropositive with respect to iron, it protects the iron fromcorroslon.

What I claim as new and desire to secure byLetters Patent of the United States is 1. The method of making a brittle alloy which consists in adding iron to zinc dross, producing therefrom a granular material of about the composition FeZn and then adding zinc to said granular material.

2. The. method of making a brittle zinciron alloy which consists in saturating heated zinc dross with iron, reducing the material to granular condition, and then 'distributingzinc uniformly throughout the granular mass. 7

3. The method which consists in adding iron to zinc until the chemical composition becomes about F eZn reducing said material to-granular condition, and then enriching with additional zinc.-

4. The method which consists. in producing a brittle zinc alloy in granular condition and then enriching said material with zinc by heating to about red heat in contact with zinc.

5. .The method which consists in maintaining zinc dross in the presence of iron at red heat until said dross becomes saturated with iron, reducing said material to granular condition, and enrichlng with zinc by heatin to about red heat in the presence of uncom ined zinc. v

6. The method of enriching with zinc a ranular mass composed largely of. zinc- 1ron alloy, which consists in heating said mass to about red heat in the presence of additional zinc. 4 7. The method which consists in tumbling zinc dross at about red heat in the presence of iron to produce a granular material consisting mainly of zinc and iron, and eriodically enriching said granular material with additions of zinc by heating to about red CHARLES F. BURGESS.

Witnesses:

HENRY CASSON, Jr., Bnssm OLESON. 

